Caryl Churchill's remarkable 1976 play is too little known. Seizing on the millennial movements that erupted during the English civil war in the 1640s, it depicts the eternal battle between revolutionary idealism and political pragmatism. As Polly Findlay's revival reminds us, in its shift to modern dress, the play also deals with issues that still burn brightly today.

In a series of short, elliptical scenes, Churchill demonstrates the fervour, much of it religious, that animated the 17th-century unrest. The king is equated with the antichrist. Parliament's mission is to build the new Jerusalem. The belief in equality is sanctioned by biblical texts.

But the great moment in Churchill's play comes when she anticipates verbatim theatre by offering an edited version of the Putney Debates of 1647. The radical Levellers, spearheaded by Colonel Rainsborough, argue for liberty and universal suffrage; the military establishment, led by General Ireton, stands for security and property as the basis for electoral eligibility. It is a pivotal moment in English history and one which Cromwell, having expressed his sympathy for Ireton, swiftly resolves by saying: "I move for a committee."

Played out on four rectangular spaces formed by an embedded crucifix, Findlay's production captures the restless volatility of the period: even the Utopian Ranters, who believe that God resides in each individual, and who exude a merry anarchy, are countered by a former agitator who foresees an England in which the poor remain permanently oppressed. The six-strong cast, including Michelle Terry, Kobna Holdbrook-Smith and Jamie Ballard, switch roles with skill and prosecute the rival arguments with ferocious zeal. Churchill's play emerges as a highly topical piece of living history, as vacuous arguments about the Big Society are used to camouflage the reinforcement of economic injustice.